1. Field of the Invention
The invention relates to a two-component pressure container box with a valve, an outer container for a first component and a foaming agent as well as an inner container sealed against the outer container for the second component and eventually another foaming agent, in which the outer container is provided with a tube extending towards the bottom of the box, and the inner container is affixed in a detachable manner and hermetically sealed against the outer container by means of sealing elements, and in which, by actuating the valve from the outside, the inner container can be opened into the outer container. Such a two-component pressure container is particularly suitable to produce two-components foams, e.g., polyurethane foams.
2. Description of the Prior Art
In particular, to produce two-component plastic foams, many techniques were developed to house separated from each other the reactive components that are necessary for the foam formation. For this, into an outer pressure container containing the prepolymer is usually inserted a second, inner pressure container with the second component, the content of which is emptied into the prepolymer by releasing it from the outside, thus mixing it with the prepolymer. The therein originated reactive mixture is then ejected by a foaming agent in the pressure container under foam formation. In known two-component pressure containers the inner container for the second component is located, e.g., in the area immediately above the box bottom. The release mechanism, by means of which is achieved the combining of the two components, is affixed at the bottom of the box and is actuated either by pressing or by twisting. By way of example, reference is made in this respect to the German registered utility patent 82 27 228 as well as to DE-A-30 22 389 and DE-A-33 22 811.
The disadvantage of these known solutions with a release mechanism in the bottom area is that, apart from the costly valve construction in the dome area of the pressure container, a second, costly molded area is necessary at the bottom of the container. On the one hand, this increases the manufacturing requirements and thus the manufacturing costs and, on the other hand, it creates a second area at the pressure container that is susceptible to influences from the outside, which must be protected against forced influences from outside by means of suitable measures, such as, e.g., the placing of gaskets, protecting caps or safety devices. Furthermore, the valve for the filling of the pressure container with a foaming agent cannot be easily arranged--as it is customary in some instances--in the middle of the chamber container.
It is further known, to arrange the inner container of a two-component pressure container directly below the valve assembly in the upper area of the pressure container. Pursuant to U.S. Pat. No. 3,635,261, an inner container arranged in such a manner below the valve assembly is placed under such a high pressure by means of a propellant-filled cartridge, affixed from the outside, that it bursts, that the content of the inner container discharges into the outer container, thus obtaining the desired mixing of the two components. Subsequently, the mixture is released in the usual manner by means of the valve.
Pursuant to U.S. Pat. No. 3,318,484 an inner container arranged in such a manner below the valve assembly is opened and discharges into the outer container because, through a downward movement of the valve, a rod arranged inside the inner container extending to its bottom acts upon the bottom in such manner that it loosens the gasket between the inner container and the mounting in the dome of the pressure container. A disadvantage in this connection is, however, that the content of the inner container can also be activated by an unintentional pressure or impact effect, resulting in a premature mixing of the components in the container. Furthermore, an actuation of the valve prior to the mixing of the two components cannot be excluded, which would result in a premature discharge of the inner container, thus rendering unusable the entire content of the pressure container because the amounts of the two components are not formulated for each other.
All in all, the hitherto known pressure containers with an inner container arranged in the upper area have proven to be somewhat unreliable, so that such pressure containers did not find acceptance on the market. On the other hand, however, the arrangement of the inner container on the inside of the valve unit is desirable in order to concentrate at one place the technically important elements of such a pressure container, which has manufacturing engineering advantages, and to keep low the number of the movable elements of such a pressure container which, in turn, has application and safety engineering advantages.
From EP-A-0 528 190 is known a two-component pressure container with an outer container for a first component and foaming agent and an inner container sealed against the outer container for the second component and, eventually, another foaming agent, in which by means of the valve the inner container can be opened to the outer container, by rotating the valve tube towards the valve seat. This can be obtained by an arrangement in which the outer container is provided at the valve disk with a tube extending to the bottom of the box, in which in the tube is placed a gear mechanism that is connected to the valve tube by an extension piece through the valve body, which under a rotary movement of the valve pipe actuates upon a journal in direction to the bottom of the pipe, and being the inner container detachably mounted at the bottom of the tube and hermetically sealed against the inside of the tube by means of a sealing element. A rotary movement of the valve tube causes a downward movement of the journal that, acting upon the inner container, irreversibly disengages it from the tube.
These two-component pressure containers have proven themselves in practical operation but, because of the journal's free movability in the tube, they require special care when filling them with propellant, when this filling shall be effected through the valve assembly. It turned out, however, that because of the suddenly occurring pressure surge during filling, the journal can be driven toward the inner container, which can lead to its premature opening into the outer container. Furthermore, the sudden pressure surge can lead to that the tube arranged at the valve disk is disengaged from its seat, dropping together with the inner container into the outer container. Although in such a case the inner container does not open into the outer container, the pressure container is ruined for the intended use.
Thus, the purpose of the invention is making available a two-component pressure container in which a second container is arranged below the valve unit, that is of easy manufacture, of safe storage and protected against an unintentional disengaging, and that makes possible a reliable disengaging with a subsequent complete mixing of both components as well as an easy filling of both the inner and the outer containers. In particular, the inner container shall be protected against an undesirable displacement when filling the pressure container with propellant through the valve.
This task is solved by means of a pressure container of the initially described type, in which the valve tube presents a contact element at its section extending through the valve body into the outer container; this contact element locks into a complimentarily formed recess in a screw assembly that meshes with an outside thread into a female thread of the tube arranged above the inner container, so that a rotary motion of the valve tube is imparted to the screw assembly by means of the contact element, separating the inner container through the thus resulting downward movement of the screw assembly. By means of the solution according to the invention, a rotary motion imparted by means of the valve stem to the valve and the therewith connected contact element is transmitted to the screw assembly and continues as forward thrust upon the inner container arranged at the end of the tube. As a result thereof, the inner container is separated from the end of the tube, so that the content, eventually under the pressure of a propellant gas, discharges into the content of the outer container, thus mixing with by an eventual shaking. A prerequisite for the separation process is, however, the rotary motion at the valve tube; thanks to the toothing of the gears a mere pressure exertion is not converted into a forward thrust.
Conventional tin containers or aluminum-drawn boxes can be considered as pressure containers.
By way of example, the tube is affixed to a concentric projection of the valve dish extending into the inside container. In particular, in the case of the tube it deals with a plastic tube that is tightly slipped over this concentric projection of the valve dish, thus extending vertically downward from the valve into the pressure container. At its valve-facing end it presents discharge openings in its wall, that render possible the passing through of the foam mass when emptying the pressure container or of the filling compound when filling the pressure container, respectively.
Of particular preference is an embodiment in which the tube presents at its valve-facing end an inside continuous groove into which engages a concentric projection of either the valve dish or, in particular, of the valve body. Instead of an inside continuous groove there can also be provided a continuous projection, extending inward in a step-like manner, or a protrusion of such type as to engage behind a continuous projection of the valve body or of the valve dish, or a combination of groove and projection.
As mentioned above, the rotary motion of the valve toward the valve seat to open the inner container is converted by a screw assembly into a downward directed movement. This is obtained by a combined action of the contact element at the bottom of the valve tube with the recess in the screw assembly. The contact element at the valve tube consists advantageously of a many-sided end piece, for example, a hexagon. However, any other embodiments of the contact element can also be used, on condition that they are provided with the toothing required for the rotary motion.
The contact element is preferably lodged or guided sliding vertically in the recess, so that by a pressing down on the valve tube it is possible to fill the container without having to separate the tube assembly with the inner container. For this purpose, a clearance is necessary between the bottom end of the contact element and the bottom of the recess, into which the contact element can slide by pressing down on the valve tube. Furthermore, the contact element and the recess are formed sufficiently long, in order to ensure a combined action up to the complete separation of the inner container with the downward-screwed screw assembly.
The valve tube, the contact element and the screw assembly, as well as the tube and the inner container, are made out of the customary suitable materials such as, e.g., a plastic, for instance polyethylene or polypropylene.
As stated above, the inner container is located at the side of the tube not facing the valve. Preferably, the upper, open end of the inner container is frictionally inserted into the tube, for which a gasket is provided between the outer wall of the inner container and the inside wall of the tube. In connection with another gasket, that is preferably formed between the screw assembly and the tube, there is obtained an effective separation of the content of the inner container from the outer container. This separation ceases to exist through the above described downward movement of the screw assembly by a rotary motion of the valve tube, inasmuch as the screw assembly pushes against the inner container pressing it out of its seating at the bottom of the tube. Thus, the content of the inner container is released and--with an adequate overpressure existing in the inner container compared to the outer container--it is also immediately ejected. The two-component pressure container is ready after the release and an eventually further shaking.
The gaskets between the inner container and the tube or between the screw assembly and the tube, respectively, are preferably formed as O-rings, that are seated in correspondingly shaped annular grooves.
The contact element is preferably arranged immediately below the disc that supports the valve tube against the bottom side of the valve body. It is advantageous for this disc to mesh into a round extension of the recess of the screw assembly, without however extending to its bottom end, so that by pressing down on the valve tube it can be pushed in farther. An annular gasket in a groove in the dish prevents the infiltration into the intake of the filling compound.
It is advantageous that the pressure container according to the invention is provided with a handling mechanism at the valve tube for a boosting of the rotary motion. This handling mechanism is screwed on to the valve tube whereby attention must be paid that the pitches of the screw thread at the valve tube and at the screw assembly or at the tube, respectively, run in such a manner as to avoid a loosening of the handling mechanism during the release. By way of example, such a handling mechanism consists of an extension of the valve tube that can be offset in the upper area, and presenting vertically projecting cross struts, that serve for the boosting of the rotary motion and, as a whole, result in a cruciform shape of the extension and the struts.
The pressure container according to the invention is also provided with a valve that can be used in both directions, which facilitates the filling of the pressure container. Thus, it is possible to fill at first the outer container with the prepolymer, e.g., a two-component foam, then to put in place the valve case with the connected and filled inner container, and finally to fill the already closed container through the valve tube and the corresponding openings in the tube with the propellant gas required for the discharge of the filling. In such a manner, the entire content of the outer container can be loaded.